Organization: National Aeronautics and Space Administration (NASA)

Research Title: Tropospheric Chemistry

Funding Level (millions of dollars):

FY94 7.3
FY95 7.5
FY96 6.8

Committee on Environment and Natural Resources (CENR) Component:
(a) Subcommittee: Global Change Research Subcommittee (90%) Air Quality Research Subcommittee (10%)
(b) Environmental Issue: Global Change (60%), Natural Variability (15%), Climate Change (15%), Air Quality (10%)
(c) Research Activity: System structure and function: (100%)

Organizational Component:
Ecology and Atmospheric Chemistry Branch
Science Division
Office of Mission to Planet Earth
NASA Headquarters
Washington, DC 20546

Point of Contact:
Robert McNeil
Phone: 202-358-0239

Research Goals:
(a) To understand the chemistry of the global troposphere and the natural and anthropogenic processes that control it, specifically processes that can lead to intermediate and long term chemical composition changes and resulting climate change. (b) To provide a chemical composition baseline in relatively clean air regions of the world against which future changes can be measured and the processes that produce them can be assessed. (c). To develop the methods and measurement protocols for future ground and airborne operations in support of EOS satellite observations.

Research Description:
This activity consists of three components: (a) airborne measurement campaigns in areas of the world where changes in population, land use, and natural inputs to the atmosphere are predicted by current understanding to have the most dramatically observable impacts on atmospheric chemical composition and, eventually, climate, because of the magnitude of the changes and/or the sensitivity of the atmosphere in the campaign areas, (b) process modeling of campaign results to build understanding and develop predictive capabilities with campaign data, and (3) instrument development to enable more sensitive and reliable data to be obtained, particularly in clean air areas where change is most readily observable.

Program Interfaces:
This activity is part of the Atmospheric Science research activity of NASA's Mission to Planet Earth. It is coordinated with other related agency activities through the Global Change and Air Quality Research Subcommittees of Committee on Environment and Natural Resources (CENR), and it receives guidance from several National Research Council committees, notably the Atmospheric Chemistry Panel of Board on Atmospheric Sciences and Climate.

Program Milestones:
By the end of the decade the program will have provided data, in many cases the only multi-component data on tropospheric chemical composition and the processes that drive it in areas of the world of great importance in assessing global chemical change and predicting the climate change that will result from it. These areas include tropical rain-forests, the Arctic tundra, sub-Arctic forests, the tropical South Atlantic, which is undergoing heavy impacts from biomass burning, and the Pacific Ocean, a clean-air region under direct and growing impact from exploding population and economic growth in Asia. Process models will have provided products bearing on the links between the observations of changing atmospheric chemistry and their links to ecosystem processes and to meteorology. These products in turn are key inputs to the global predictive and assessment models under development in other areas of the global change research program.

Policy Payoffs:
(a) The reliability of global scale assessment and predictive models is directly tied to the availability of key data on the global system. Global atmospheric chemistry, particularly in the troposphere and lower-stratosphere is an essential element in any global change or climate change scenario. It is known to be changing because of human activities, which emit pollutants directly and also affect the natural system, which is also a major source-sink region for the chemical components of the atmosphere. In addition to providing highly relevant data and understanding in its own right, global atmospheric chemistry studies will develop the instrumentation, sampling protocols, and platforms for the ground- based and airborne activities needed to support and validate the global observations planned with the EOS. The policy payoff from this task is that it will provide a major portion of an extremely critical data base, establish a basis for understanding global observations, and contribute to the credibility and robustness of the technical underpinnings for future policy actions to deal with global change.